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EnHAnCEMEnT　OF　InTRAMOLECULAR　EXCIMER　FORMATIOn　AnD　PHOTODIMERIZATIOn　OF　POLYETHERS　BEARInG　nAPHTHALEnE　chROMOPHORES　VIA　COMPLEXATIOn　WITH　CATIOnS

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ch.nese chemical Letters 1995年第2期6卷 113-116页

作者： Tung, ch Wu, LZ Acad Sinica Inst Photog Chem Beijing 100101 Peoples R China

The fluorescence spectra and photodimerization of naphthalene end-laballed poly(ethylene glycol) oligomers (n-Pn-n) in methanol in the prescence of alkali cations have been investigated. The ion enhances or inhibits intramolecular excimer formation and photodimerization of n-Pn-n, depending on the size of the ion and the length of the polyether chain. This observation suggests that the polyether chain binds the ion, thus adopts a crown ether-like conformation.

关键词： VIA chROMOPHORES COMPLEXATIOn WITH nAPHTHALEnE AnD BEARInG

Monazite recorded Paleoproterozoic granulite-facies metamorphism and Triassic fluid modification of the Weihai pelitic granulite,Sulu orogen

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Science ch.na Earth Sciences 2021年第6期64卷 932-950页

作者： Zhiwu xiong Haijin XU Pan WAnG Junfeng ZHAnG School of Earth Sciences China University of GeosciencesWuhan430074China

Monazite is an important accessory mineral in the pelitic granulites(Weihai area,Sulu orogen),and is also a powerful monitor for understanding the metamorphic evolution of the *** pelitic granulites incongruously occur as lenses in granitic *** lithologies of the lenses gradually ch.nge from core to margin:The undeformed coarse-grained granulite,the foliated fine-grained granulite,the garnet-biotite-gneiss,and the migmatized *** lens cores mostly preserve a peak granulite-facies metamorphic mineral assemblage of garnet+plagioclase(antiperthite)+quartz+sillimanite+biotite with accessory minerals of rutile,zircon,and *** lens margins display a fluid-induced *** order to decipher the metamorphic processes of the pelitic granulites,a combined study of BSE imaging,U-Pb dating,and trace element composition for the monazites from the metapelitic lens were *** from the undeformed coarse-grained granulite only record a Paleoproterozoic age(1832±7 Ma,n=40).Monazites from the other lithologies yield the inherited Paleoproterozoic age and Triassic overgrowth *** example,monazites from the migmatite yield intercept ages of 1818±10 and 211±22 Ma(n=56)with Triassic concordant age of 223.8±2.9 *** Paleoproterozoic monazites are characterized by remarkable depletion in HREE and Y with obviously negative Eu anomalies,indicating their formation equilibrated with garnet and feldspar under granulite-facies *** Triassic fluid modification,the monazite bright rims assimilated Th and Si but released U,HREE,Y,and *** process resulted in that the Triassic overgrowth monazites have higher HREE and Y contents,and lower Th and U contents with relatively low Th/U ***,the monazites in the pelitic granulites recorded a Paleoproterozoic metamorphic event and Triassic fluid *** Weihai pelitic granulites might have a tectonic affinity with the north ch.na ***,the Paleoproteroz

关键词： Pelitic granulite Monazite Paleoproterozoic Triassic Sulu orogen

Oxidation behavior of boron-containing(Zr,Ti)C_(x)B_(y)solid solution ceramics at 1600℃in air

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Journal of Advanced Ceramics 2023年第10期12卷 1989-2002页

作者： Huilin Lun Yi Zeng Xiang xiong Houbu Li State Key Laboratory of Performance and Structural Safety for Petroleum Tubular Goods and Equipment Materials CNPC Tubular Goods Research InstituteXi’an 710077China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Key Laboratory of Petroleum Tubular Goods and Equipment Ouality Safety for State Market Regulation CNPC Tubular Goods Research InstituteXi’an 710077China

Multicomponent boron-containing carbide coatings(i.e.,(Zr,Ti)C_(x)B_(y))on a C/C composite show good ablation ***,the high-temperature oxidation behavior of this new type of boron-containing(Zr,Ti)C_(x)B_(y)solid solution ceramics has not been clarified *** present work fabricated(Zr,Ti)C_(x)B_(y)solid solution block ceramics by spark plasma sintering,and their oxidation behavior at 1600℃in air(n2–20-vol%O2)was investigated for the first *** effects of boron on the oxidation resistance of(Zr,Ti)C_(x)B_(y)ceramics were *** results indicate that the(Zr,Ti)C_(x)B_(y)ceramics display good oxidation resistance with the parabolic rate law describing the oxidation *** the trace solution of boron(0.5 wt%)into(Zr,Ti)Cx,the oxidation resistance of carbide ceramics is significantly enhanced,leading to a decrease of 30%in the oxidation rate *** formed oxide scale in the(Zr,Ti)C_(x)B_(y)ceramics is dense,and the interlayer shows stronger ability to inhibit inward diffusion of *** addition,the introduction of boron leads to more negative binding energy of(Zr,Ti)C_(x)B_(y)and improves the oxidation resistance of carbides.

关键词： ultra-high-temperature ceramics(UHTCs) (Zr,Ti)CxBy solid solution oxidation behavior oxidation resistance

Coupling mech.nism of activated carbon mixed with dust for flue gas desulfurization and denitrification

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Journal of Environmental Sciences 2020年第12期32卷 205-214页

作者： Junxiang Guo Yuran Li Jin xiong Tingyu Zhu Beijing Engineering Research Center of Process Pollution Control National Engineering Laboratory for Hydrometallurgical Cleaner Production TechnologyInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

To clarify the effect of coking dust, sintering dust and fly ash on the activity of activated carbon for various industrial flue gas desulfurization and denitrification, the coupling mech.nism of the mixed activated carbon and dust was investigated to provide theoretical reference for the stable operation. The results show that coking dust had 34% desulfurization efficiency and 10% denitrification efficiency;correspondingly, sintering dust and fly ash had no obvious desulfurization and denitrification activities. For the mixture of activated carbon and dust, the coking dust reduced the desulfurization and denitrification efficiencies by blocking the pores of activated carbon, and its inhibiting effect on activated carbon was larger than its own desulfurization and denitrification activity. The sintering dust also reduced the desulfurization efficiency on the activated carbon while enhancing the denitrification efficiency. Fly ash blocked the pores of activated carbon and reduced its reaction activity. The reaction activity of coking dust mainly came from the surface functional groups, similar to that of activated carbon. The reaction activity of sintering dust mainly came from the oxidative property of Fe_2O _3, which oxidized nO to nO_2 and promoted the fast selectively catalytic reduction(SCR) of nO to form n_2. Sintering dust was activated by the joint action of activated carbon, and both had a coupling function. Sintering dust enhanced the adsorption and oxidation of nO, and activated carbon further promoted the reduction of nO_x by nH_3;thus, the denitrification efficiency increased by 5%-7% on the activated carbon.

关键词： Activated carbon Coking dust Sintering dust Fly ash Coupling effect

Micro-Macro Scale Relationship in Creep Deformation of Ultra High Molecular Weight Polyethylene

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ch.nese Journal of Polymer Science 2021年第12期39卷 1665-1672页

作者： Bi-Jin xiong Zhen-Xian ch.n Jian Kang Key Laboratory of Materials chemistry for Energy Conversion and Storage(HUST)of Ministry of Education School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology(HUST)Wuhan 430074China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu 610065China

Macroscopic and microscale creep deformations of UHMWPE were investigated by using in situ SAXS.A methodology for the measurement of the local creep deformation of inter-lamellar amorphous phase has been *** local strain of inter-lamellar amorphous phase(£a)and macroscopic strain(£macro)were evaluated and they were compared to study the relati on ship betwee n macroscopic and microscale creep deformation of *** of them exhibit two deformation regions against creep *** entanglements show a strong impact on both the macroscopic and local inter-lamellar amorphous phase creep behavior and they can be well correlated to the molecular weight between two entanglements estimated from strain-hardening *** to the macroscopic creep deformation,local inter-lamellar amorphous layers have a smaller creep *** the local creep measurement,the apparent modulus of inter-lamellar amorphous phase can also be estimated(200ch higher than the Young's modulus of bulk amorphous PE,which can be well explained by the confinement of the lamellar stacks and the enhancement of the amorphous phase with the relatively high concentration of *** study provides a useful means and quantitative data for achieving the scale transition between the micro and the macro structural levels for the study of viscos-elastic deformation.

关键词： Ultra-high molecular weight polyethylene Creep Small angle X-ray scattering Microscale

First-principles study of defect control in thin-film solar cell materials

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Science ch.na(Physics,Mech.nics & Astronomy) 2021年第3期64卷 28-45页

作者： Hui-xiong Deng RuYue Cao Su-Huai Wei State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Computational Science Research Center Beijing 100193China

A solar cell is a photovoltaic device that converts solar radiation energy to electrical energy, which plays a leading role in alleviating global energy shortages and decreasing air pollution levels typical of conventional fossil fuels. To render solar cells more efficient, high visible-light absorption rates and excellent carrier transport properties are required to generate high carrier levels and high output voltage. Hence, the core material, i.e., the absorption layer, should have an appropriate direct band gap and be effectively doped by both p-and n-types with minimal carrier traps and recombination centers. Consequently, defect properties of absorbers are critical in determining solar cell efficiency. In this work, we review recent first-principles studies of defect properties and engineering in four representative thin-film solar cells, namely CdTe, Cu(In,Ga)Se2, Cu2ZnSnS4, and halide perovskites. The focal points include basic electronic and defect properties, existing problems, and possible solutions in engineering defect properties of those materials to optimize solar cell efficiency.

关键词： first-principles study thin-film solar cells defect engineering energy conversion efficiency

On THE EMPTY BALLS OF A CRITICAL OR SUBCRITICAL BRAnch.nG RAnDOM WALK

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Acta Mathematica Scientia 2024年第5期44卷 2051-2072页

作者： Shuxiong ZHAnG Jie xiong School of Mathematics and Statistics Anhui Normal UniversityWuhu241002China Department of Mathematics and SUSTech International Center for Mathematics Southern University of Science and TechnologyShenzhen518055China

Let{Z_(n)}_(n)≥0 be a critical or subcritical d-dimensional branch.ng random walk started from a Poisson random measure whose intensity measure is the Lebesugue measure on R^(d).Denote by R_(n):=sup{u>0:Z_(n)({x∈R^(d):∣x∣ntered at the origin of Z_(n).In this work,we prove that after suitable renormalization,Rn converges in law to some non-degenerate distribution as n→∞.Furthermore,our work shows that the renormalization scales depend on the offspring law and the dimension of the branch.ng random *** completes the results of Révész[13]for the critical binary branch.ng Wiener process.

关键词： empty ball dimension branch.ng random walk super-Brownian motion

A branch.ng particle system approximation for nonlinear stochastic filtering

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Science ch.na Mathematics 2013年第8期56卷 1521-1541页

作者： LIU HuiLi xiong Jie Department of Mathematics Hebei Normal University Department of Mathematics and Statistics Concordia University Department of Mathematics University of Tennessee

The optimal filter 7r = {π,t ∈ [0, T]} of a stochastic signal is approximated by a sequence {Try} of measure-valued processes defined by branch.ng particle systems in a random environment （given by the observation process）. The location and weight of each particle are governed by stochastic differential equations driven by the observation process, which is common for all particles, as well as by an individual Brownian motion, which applies to this specific particle only. The branch.ng mech.nism of each particle depends on the observation process and the path of this particle itself during its short lifetime δ = n-2α, where n is the number of initial particles and ~ is a fixed parameter to be optimized. As n → ∞, we prove the convergence of π to πt uniformly for t ∈ [0, T]. Compared with the available results in the literature, the main contribution of this article is that the approximation is free of any stochastic integral which makes the numerical implementation readily available.

关键词： optimal filter branch.ng particle system uniform convergence numerical solution

Visible-light degradation of azo dyes by imine-linked covalent organic frameworks

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Green Energy & Environment 2023年第1期8卷 194-199页

作者： Hongbo Xue Sen xiong Kai Mi Yong Wang State Key Laboratory of Materials-Oriented chemical Engineering And College of Chemical EngineeringNanjing Tech UniversityNanjing211816JiangsuChina

Covalent organic frameworks(COFs)are nanoporous crystalline polymers with densely conjugated *** work discovers that imine-linked COFs exhibit remarkable photodegradation efficiency to azo dyes dissolved in *** light generates different types of radicals from COFs,and superoxide radicals break n=n bonds in dye molecules,resulting in 100%degradation of azo dyes within 1 *** contrast,these dyes cannot be degraded by conventionally used photocatalysts,for example,***,the COF photocatalysts can be recovered from the dye solutions and re-used to degrade azo dyes for multiple times without loss of degradation *** work provides an efficient strategy to degrade synthetic dyes,and we expect that COFs with designable structures may use as new photocatalysts for other important applications.

关键词： Covalent organic frameworks Dyes Photocatalytic degradation Porous polymer Water pollution